On a psychological level, facial retouching is complex and not just a question of “correcting” problems. The face is the first place we look at when we look at another person and the most common ways to retouch a face (eyes, mouth and skin) can make someone look friendlier, more reliable or more interesting. There are studies that have demonstrated that in a matter of milliseconds we decide if a face is trustworthy, if the skin is clear or not or if the person is smiling or not. If we retouch the face without making it look fake or unnatural it will be perceived as real. If we overdo it, it will create an uneasy feeling because our brain will realize that something is not quite right (this is why some people call it “the valley of the uncanny.”)
Specifically, the eyes. Catchlights that are ever so slightly overbrightened, the right amount of filling of under-eye circles, an appropriately defined shape to the eyebrows, a little too much softness to the eyelids, but not to the extent of looking unnatural. People respond to all of these things because we’re wired to recognize the signs of an open eye that’s not merely alert, but active. Anything that smoothes the transition between the mouth and nose will do wonders to help the eyes create the impression of a sincere smile. A good retoucher never tries to create an entire new face; they’re just trying to help the face be a more coherent expression of the person’s personality.
The structure of the skin is also important. When an image shows perfect, doll-like skin, our brains react badly because it doesn’t match the pattern of what we expect from a real human. Light retouching preserves the skin’s micro-texture, evening out only the things we don’t want to see — the red of a pimple, the light or dark spot that resulted from a flash reflection, or some transient condition that we don’t think of as part of a person’s character. Leaving the residual surface intact leaves the person’s history: the nascent creases of smile lines, the soft creases of crows’ feet, the gentle sprinkle of freckles. With those lines and marks, we can empathize with that face. Without them, we just see an unrealistic beauty.
Another factor to consider is the color harmony. We can say a lot about the face by its undertones. A warm face may look friendly and inviting, while a cool face can be perceived as aloof and glamorous. We also make sure to adjust the color tone so that the face will look healthy and not too grayish or too saturated, which is a dead give away that the face has been retouched. Sometimes, when needed, we will also subtly color the lips and cheeks to make the face look happy and healthy (more rosy), or maybe less aggressive (less rosy). Again, it all depends on the image, if we want to convey a message of security and self assurance or maybe to look peaceful and loving.
Understanding the psychology behind minor tweaks makes retouching a form of visual empathy. It’s not only about technical ability; you also have to understand the way faces convey personality and emotion. Done tastefully, these tweaks don’t obscure the truth; they show it more sharply. The most compelling portraits are those where you feel like you see the individual in the picture, rather than a character they’ve assumed. That line between enhancing the photograph while still preserving the truth of it is the difference between good editing and good art that will stay in your memory after the photograph has left your eye.